In the current state of integrated circuit technology, transistors are typically heavily incorporated into integrated circuits in order to perform a number of functions. In an effort to improve circuit functionality, e.g., for power amplifier circuits, transistors, such as heterojunction bipolar transistors (HBT) and field effect transistors (FET), have been co-integrated on single gallium arsenide substrates.
Co-integrating transistor devices sometimes involves compromising between manufacturability, cost and device performance. For example, for some applications, co-integrating an enhancement mode FET (EFET) with one or more other transistors (e.g., with depletion mode FETs (DFETs), HBTs, etc.) may have a higher cost implication.